This invention relates to peroxyacid bleaching particles comprising an inner core of a solid peroxyacid compound and as a coating a surfactant compound.
Peroxygen bleaching agents in general and peroxyacid compounds in particular have long been recognized as effective bleaching agents for use when the adverse color and fabric damage effects of harsh active halogen bleaching agents cannot be tolerated. See, for example, Canadian Pat. No. 635,620, Jan. 30, 1962, to McCune. Utilization of peroxyacid materials in commercial bleaching products, however, poses several problems. Liquid bleaching compositions containing peroxyacid materials as the active bleaching agent have the tendency to diminish in bleaching effectiveness over prolonged storage periods. Likewise, granular bleaching products containing peroxyacid compounds also tend to lose bleaching activity during storage, as well as pose a safety problem due to their exothermic decomposition properties.
An additional problem present is that the dissolution rate of peroxyacids decreases with shelf life due to the decomposition of the peroxyacid. The decomposition results in formation of the acid used to make the peroxyacid, whose presence causes the solubility rate of the acid/peroxyacid mixture to be reduced to an unacceptable level. The decreased solubility equates with poorer bleaching effectiveness and possible fabric and dye damage which are undesirable.
It has been discovered in the present invention that the solubility of solid peroxyacids can be maintained by coating the peroxyacid particles with a surfactant compound. This development allows the formulator of peroxyacid bleach products to formulate products which maintain bleach effectiveness and fabric safety through improved solubility over an extended shelf period.
It is, therefore, an object of the present invention to provide bleaching particles comprising a peroxyacid compound as an inner core and a surfactant compound as a coating.
It is another object of the present invention to provide a method for making the bleach particles.
It is still another object of the present invention to provide improved bleaching compositions.
It is yet another object of the present invention to provide an improved method for bleaching fabrics.
These and other objects are obtained herein, as will be seen from the following disclosure.
All percentages and ratios herein are by weight unless otherwise designated.